Moistureproof coating



- Patented Mar. 11,1941

UNITED STATES PATENT OFFICE MOISTUREPBOOF COATING Daniel D. Iiannlng, Kenmore, N. Y., assignmto E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application September 8, 1937, Serial No. 162,888

18 Claims.

fibrous cellulosic materials containing moisture proof coatings are well known as wrapping tissue. In general, the coatings of such sheets and films comprise a film-forming constituent such as a cellulose derivative or a resin, a moistureproofing agent such as a. wax, a blending agent such as a resin, and a plasticizer. Such moistureproofing coating compositions and methods for compounding and applying the same are 20 disclosed in detail in the U. S. Patent No.

1,737,187 to Charch and Prlndle and French Patent No. 718,440 to Charch.

Difficulty has long been experienced in the handling and storing of such sheets and films because of their lack of slipperiness and adherence of contiguous sheets to each other. These diificulties are due to at leasttwo factors. One factor is that some of the constituents of the moistureproofing composition may be inherently tacky. A second factor is that the surfaces of these sheets are so-smooth that, when they lie in close juxtaposition, they have a tendency to exclude air from between them, thus causing a 35 vacuum action which renders it very dimcult to separate the sheets, and at the same time to increase the area of contact, thus increasing the coeflicient of friction. This smoothness is not overcome and in fact is accentuated by the ordinary constituents of the moistureproofing composition, particularly the moistureproofing agent, since it apparently forms 'a smooth continuous phase in order to prevent the passage of moisture.

Furthermore, it has been observed that these difficulties are greatly augmented by a slight rise in temperature. A sheet which proves perfectly satisfactory as to surface conditions at ordinary room temperatures may become very tacky and unmanageable when stored in heated places or when subjected to abnormally high Similar conditions have room temperatures. been found to arise in the use of automatic degree of. stickiness and frictional resistance, while an inconvenience, is of no considerable consequence. It becomes of extreme importance, however, when such adherence and frictional resistance is increased by the transmission of heat or the heat developed by friction in an automatic machine. It is found actually that a difierence of 1 or 2 may even cause a sticking of the material to some part or other'of the machine and completely foul its operation. Furthermore, due to the high speeds developeg in such automatic machinery, normal adher nce and frictional resistance, even of the same degree as can be tolerated in manual operation, are objectionable even in the absence of a temperature rise.

An attempt has been made to overcome the adhesive tendency inherent in these films by the use of a thin layer of talcum powder. Thismethod has the disadvantage, however, that while it lessens the adhesion of the sheets, it stains the It has been suggested to incorporate small amounts of finely divided, insoluble materials, such as kaolin, aluminum hydroxide, titanium oxide, etc. in the moistureproofing coating compositions which are to be-applied to the film. Since this solid matter is in a very finely divided form and since the coating bath is of relatively so high viscosity, it is possible to disperse these solid particles in the bath and apply evenly to the surface of the film. The presence of such solid matter producesnumerous points of separation between contiguous sheets in stacked rea lation, or between the surface of the sheet and other smooth surfaces, and thus insures'good surface slip. However, the introduction of insoluble matter into the bath composition has several disadvantages. For one thing, it is very diificult to adequately disperse such solid materials without prolonged stirring and agitation and the dispersion may not be stable over long Peri ods of time or in all conditions of operation, so

that pipelines and apparatusmay become clogged a lowering of the moistureproof quality which is wrapping machinery. As long as such wrappingtissue is manually applied topackages, a slight perhaps caused by interference with the continuity of the w'ax surface. u

duce a transparent, non-fibrous sheet or film containing a moistureproofing coating comprising a solvent soluble slip agent, which sheet or film will be substantially non-adherent at 'elevated temperatures.

Other objects of the invention will" appear hereinafter.

The objects of the invention may, generally, be attained by the use of a moistureprooflng coating composition containing a solvent soluble, double metallic carboxylate which will be completely soluble in the liquid composition but which will not be completely compatible with the other constituents of the' composition in its final dry state and which will therefore be present in a distinct phase from that of the main body of the coating.

Although any double metallic carboxylate can be used provided it has the above solubility and compatibility requirements, the following test sets forth a convenient method for determining the requisite characteristics of the most useful substances:

First, test the solubility of the substance in toluene atroom temperature, or approximately 25 C. To function as a slip agent in the sense of this invention, it must be: soluble to the extent of 1% or more. Second, place 0.5 gram of the material in a test tube, add 25 cc. of acetone,

. place a stopper in the tube and shake. In this test also the temperature of the solvent should be approximately 25 C. To function as a slip agent, the material must be partially or completely insoluble. If it is completely soluble, it will not motion as a slip agent.

It is desirable that the slip agents separating in a distinct phase from the coating composition upon'the removal of the solvent shall have approximately the same optical characteristics as the coating composition itself. It therefore should preferably be substantially colorless (or at least colorless in the concentration present in the final film) and have approximately the same index of refraction as the coating composition, such that the resulting product will appear transparent. The materials of the present invention are well suited "for this purpose. The following examples which are to be considered illustrative and not limitative will assist in an understanding of the invention.

'The solvent soluble slip agents of the present invention should preferably have the characteristic-of raising the stick temperature" (defined in detail below) of the coating composition above 55 C.

For the purposes of comparison and definition,

the following test is used to determine the stick temperature; A web of the material to be tested is moved across a table top and below a brass of about 7 C. per minute, and the frictional drag upon the filmv observed. This frictional drag at low temperatures is about 50-100 grams; at some elevated temperature it increases suddenly to several thousand grams, and the temperature at which this occurs is taken as the stick temperature.

As the double metallic carboxylates there may I be used a double metal salt of a single carboxylic 5 acid,-of which zinc-aluminum rosinate is an example. or a single metal salt of two carboxylic acids, such as the aluminum salt of rosin and modified rosin, the aluminum-salt of Petrex resin and modified rosinand the aluminum salt of i0 phthalic acid and benzoyl benzo-ic acid. Other combinations are possible, such as salts of two metals and .two acids. Likewise, more than twometallic or acid radicals may be present in the compound. The term double metallic carboxyll5 ate, unless otherwise modified, is understood to include all these varieties. c

The double metallic carboxylate should preferably be so selected that one of the corresponding single salts is highly soluble in the solvents 20 used, suchv as toluene and ethyl acetate. and therefore presumably highly compatible with the other solids of the coating composition. The other corresponding single salt, on theother hand, should be of limited solubility. in such sol- 25 vents, and therefore only slightly compatible with Y coating baths containing salts of certain organic acids which have been found to give excellent surface conditions and transparency when applied to transparent regenerated cellulose film. 40 In each case the stick temperature, as above defined, will be found given.

Table Example Number Part: Purl: Part: Parts W y by 50 weight weight weight weight Double metallic salt 8 6 1 Nitrocellulose, 11.6% N 62 62 62 51 Modified rosin. 7 1i 9 15 Paraffin wax 3 3 3 3 Dibutyl phthalate l5 l5 l5 l5 Dicyclohexyl phthalat l5 l5 l5 l5 Ethyl aoetate 440 440 440 440 Toluene 271 271 271 271 Ethyl aloohol 22 22 22 22 Stick temperature, "C 60 7i 62 59 m the above table, the double metallic salt of Example 1 is aluminum rosinate modified rosinate; of Example 2, aluminum zinc rosinate;

of Example 3, aluminum salt of Petrex acid and of modified rosin; of Example 4, aluminum phthalate benzoyl benzoate. In each case the amount of the negative radicals or, in the case of Example 2, of the positive radicals are equal to each other. I

The material which is added as a slip agent to the coating composition may also contribute 7 other valuable properties to the coating. For

instance, it may contribute tothe body of the coating and serve to a certain extentms a blending agent for the wax and the nitrocellulose. In

other cases the slip agent added may aid in 76 v 2,934,500 softening and plasticizing the coating. Advantage may be taken of such properties to so modify the coating composition as to effect a saving in some of the other ingredients such. as resin, blending agent, and plasticizer.

The slip agents of thepresent invention may be incorporated by any suitable method, preferably by dissolving in asuitable solvent such as toluene and then incorporating the remaining viously known insoluble slip agents'may be in-,

troduced by the following method:

Cellulose nitrate in any formsuch as powder,

flake, fiber or the like, is immersed in an aquein the art will serve.

ous solution of certain water soluble salts, such as aluminum. sulfate or zinc acetate. then followed by treatment with a solution such as ammonium hydroxide or sodium abietate which precipitates an insoluble ,slip agent on the pyroxylin structure. The treated cellulose nitrate is dried or dehydrated with alcohol and used directly in preparing lacquer solutions. The method is very effective in producing moistureproof lacquers for regenerated cellulose film exhibiting good slip properties.

Still another general method of introducing silicon containing slip agents is represented by the following example. Silicon compounds, either organic such as ethyl silicate or inorganic such as silicon tetrachloride, which react with water or alcohol to precipitate silicic acid may be added to lacquers containing water and/or alcohol to produce a finely divided dispersion of silicic acid or an intermediate product of hydrolysis'which is eifective in producing lacquers with good slip.

The slip agents of this invention must be completely soluble in the solvent mixtures of the coating compositions, although they need not be soluble in every individual solvent of the solvent mixture. For this purpose any of the usual solvents and solvent mixturesfamiliar to one skilled Generally speaking, the solvent will contain a cellulose derivative solvent and a wax solvent as well as a solvent for the resin and optionally a; diluent. It is apparcut that the same solvent may serve for two or more constituents and indeed, it may be that the cellulose derivative solvent will also be a wax solvent. The solvent mixture comprising 40-90% ethyl acetate, -50% toluene, and the balance ethyl alcohol will usually be found to operate satisfactorily. Depending on the amount and nature of the cellulose derivative or of the wax, or of the slip agent. etc., the amount and nature of the respective solvents will vary. Satisfactory solvents for the specific compositions are illustrated in the accompanying examples.

In the preparation of a transparent, moistureproof wrapping tissue a suitable wax-containing composition comprising a cellulose derivative and a solvent soluble-slip agent may be applied to the desired base in accordance with the methods known to the art. The solvents may be removed,

and the coated material subjected to an elevated temperature at least equal to the melting Point of the wax, whence a clear, transparent, moistureproof film may be obtained. The technique of this procedure is set forth in such patenisas the Charch and Prindle Patent No. 1,737,187.

While this invention has been described in terms of a coating composition comprising a cellulose derivative and certain other constituents applied to a base film of regenerated cellulose or This is.

other materials, it will be understood that its equally applicable to the preparation oi'self sustaining films of cellulose derivatives which are formed by extrusion. or casting, or'other,

means from a solution in which the desired slip agent is more soluble than in the resulting film.

Moistureproofing coating compositions may be used on various non-fibrous, transparent base sheets including sheets or films of regenerated cellulose, whether they be made by the viscose process, the cuprammonium process, or by any other manufacturing technique; cellulose ethers such as ethyl, benzyl or glycol cellulose; cellulose esters such as cellulose nitrate or celluose acetate; lowly etherified cresterified materials such as lowly etherified ethyl cellulose, lowly etherified benzyl cellulose or lowly etherified glycol cellulose, and lowly e'sterified cellulose nitrate or lowly esterified cellulose acetate; gelatin, casein, or the like.

In preparing moistureproofing coating compositions comprising solvent soluble slip agents, it has been found that the best results are obtained by limiting the relative amounts of the several constituents. The amount of film-forming constituent, for example, may vary from 30-70% or more of the total solids although in most instances 50-60% is to be preferred.

The solvent soluble slip agent may be present in amounts of the order of 1-40% ,of thetotal solids, depending upon its compatibility with the rest of the constituents of the coating composition when in the final dry state. The amount of the solvent soluble slip agent used in a coating composition must be such that it will be completely soluble in the liquid coating composition but will, after removal of the solvent, separate at least partially from the main body of the coating. Preferably it should be present in such quantity that the separate phase will constitute only a small proportion of the total coating, such as 5% or less. r

The wax content of these moistureproofing compositions may vary from 0.5%, or 1% to 10%, or more of the total solids content. Usually about 4% is satisfactory, although more or less may be found desirable for different purposes.

' The amount of plasticizer may vary, of course, from none at all up to about 40 or 50% of the solids content of the composition.

The amount of solvent or solvent mixture may vary according to the composition and to the method of application, or. purpose desired. The

viscosity of the coating composition may be controlled by the amount or nature of the solvent and may be adjusted easily to adapt the solution for coating by brushing, spraying, dipping or any other methods familiar to the art.

Where percentages and proportions of ingredients are referred to throughout .the specification and claims, they are intended to be percentages by weight, or parts by weight.

The term modified rosin as used throughout the present specification and claims is defined as the rosin described and claimed in U. S. Letters Patent to Morton, No. 2,017,866; that is to say, a rosin having a high melting point, a high molecular weight, and being materially decolorized. This modified rosin is characterized generally by properties similar, to those of rosin, but with the difference that it has a molecular weight within the range 5% to 400% greater than ordinary rosin inits pure state: that it has a melting point, as determined by the capillary tube method, above 85 C. and higher 'viously available.

of purified rosin when in the resinous state; that it is substantially free from combined sulfur and hardening substances held in combination; that it has an iodine value lower than that of pure abietic acid; and that it has a molecular weight higher than that of pure abietic acid.

7 The term "Petrex as used throughout the present specification and claims is defined as the terpinene malelc anhydride complex comprising essentially 3 isopropyl 6 methyl-3:6-endoethylene-delta-4-tetrahydro phthalic anhydride (J. Ind. Eng. Chem. XXIX, 21) marketed as "Petrex resin by the Hercules Powder Co. It has an acid munber of approximately 530, a molecular weight of approximately 215, and a softening point of 40-50 C.

The surface conditioning agent of the present invention, when incorporated in coating compositions for use with transparent, cellulosic wrappin tissue, has been found to give a product which is eminently suited for use upon automatic wrapping machinery. For such use it is necessary that the tightly wound rolls of material supplied for use upon such machines unwind and deliver the film very smoothly and evenlythrough the machine. Even though rolls of such material have been tightly wound and stored at relatively high temperatures, it is found that there will be absolutely no sticking between the surfaces of the film, allowing it to unroll with great ease and freedom from tears, marred surfaces and other blemishes. It is furthermore essential that such material will pass evenly and smoothly through the whole course of the wrapping machine without adherence to various portions of said machine. Very often, certain heated elements form a part of such machines, said elements generally being used for the formation of heat seal at a certain stage of the wrapping operation. Should the adjacent parts of the machine become warm by conduction or convexion of said 'heating elements, serious trouble may result in the operation of the machine by sticking of the wrapping tissue to these surfaces. The present invention produces a wrapping tissue which is far less likely to adhere to such surfaces than wrapping tissues pre-' Where the coated wrapp ng tissue is in the form of sheets, said sheets may be stacked and stored for long periods of time without any ep- .pearance of adhesion between the sheets so stacked. Such sheets may be readily separated and handled manually or by machinery.

The method and materials of this invention produce an improved surface without adversely anecting clarity to the extentencountered-in the use of the previously known insoluble slip agents.

In coating compositions giving moistureproofness, this moistureproofness is not aflected so much by the solvent soluble slip agent as with previous insoluble slip agents. v y

The method of the invention has the very im-Z portant advantage of giving a more uniform distribution of the surface conditioning agent throughout the coating bath which results'in a far more even distribution in the coating with the elimination of certain optical defects in the transparent film. Furthermore, it is possible to filter and purify the bath Just before application to the film, making possible a very high" grade product. Such filtration is not possible where the agent added is a dispersed solid so 9,234,565 than the melting point of pure abietic acid and that large, solid particles and impurities that might occur in the bath at its later stages of preparation would remain to give trouble in the coating machinery and final product.

' Not only may the use of the material be more precisely and rigidly controlled, but the disadvantages incident to sedimentation when the prepared bath solution is stored for a period of time, or transferred through pipes and under conditions which might cause the flocculation and sedimentation of a solid constituent are avoided.

By incorporating, the double salts of the present invention in the coating composition, it is possible to obtain good slip in the coated surface over a much wider range of salt concentration than if the single salts of the same metals and acids are used. In some cases, the corresponding single salts, for example, are of only limited solubility in the solvents used, so that only limited quantities can be used. In other cases, the single salts are so highly compatible with the solid constituents of the coating composition that it is necessary to use very large quantities.

Since many changes and modifications can obviously be made from the details of the above description without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited except as set forth in the following claims.

I claim:

1. A moistureprooiing coating composition containing, dissolved in an organic solvent, a film-forming ingredient, a wax moistureprooflng agent and the aluminum salt of rosin and modifled rosin, said modified rosin being characterized by properties of the general nature of those of rosin, but with the difference that it has a molecular weight within the-range 5% to 400% greater than ordinary rosin in its pure state; that it has a melting point, as determined by the capillary tube method, ,above 85 C. and higher than the melting point 'of pure abietic acid and of purified rosiif'when in the resinous state; that it is substantially free from combined sulfur and hardening substances held in combination; that it has an iodine value. lower than that of pure abietic acid; and that it has a molecular weight higher than that of pure abietic acid, said salt being present in sumcient quantity to separate as a distinct phase after the removal of the solvent,- but in insuflicient quantity to substantially impair the transparency of the coating.

2. A moistureproofing coating composition containing, dissolved in an organic solvent, a

film-forming ingredient. a wax moistureprooflng agent and zinc aluminum rosinate, said rosinate being present in sufilcient quantity to separate as a distinct phase after the removal of the solvent but in insumcient quantity to substantially im .pairthe transparency of the coating.

3. The article of claim 9, in which the double I metallic carboxylate is the aluminum salt of rosin and modified rosin. said modified rosinbeing by properties of the general nature of those of rosin, but with the diflerence that it has amolecular weight within the range 1 5%.to 400% greater than ordinary rosin in its pure state; that it has a melting point, as dethan that of pure abietic acid;. and that it has a molecular weight higher than that of pure abietic acid.

4. The article of claim 9 in which the double metallic carboxylate is zinc aluminum rosinate.

5. A thin, flexible, slippery, non-fibrous, transparent sheet provided with amoistureproofing coating, said coating containing 30%-'l0% of a film-donning ingredient, 0.5%-10% of a wax moistureproofingagent, and 1%-40% of a slip agent, said slip agent being in a phase separate from the main body or the coating and being from the group consisting oi the aluminum salt of rosin and modified rosin, the aluminum salt of Petrex acid and modified rosin, aluminum salt or phthalic acid and benzoylbenzoic acid, and zinc aluminum rosinate, and having a solubility of at least 1% in toluene at a temperature of 25 C., and 0.5 grams of said carboxylate,

nary rosin in its pure state; that it has a melting-point, as determined by the capillary tube method, above 85 C. and higher than the melting point "or pure abietic acid and of purified rosin when in the resinousstate; that it is substantially free from combined sulfurand hardening substances held in combination; that it has an iodine value lower than that of pure abietic acid; and that it has a molecular weight higher than that of pure abietic acid,- and said Petrex acid being a terpinene maleic anhydride,

complex comprising essentially 3-isopropyl-6- methyl-3:6-endo ethylene de1ta-4-tetrahydro phthalic anhydride.

6. A thin, flexible, slippery, non-fibrous, transparent sheet provided with a moistureproofing coating, said coating containing 30%-70% of a film forming ingredient, 0.5%-10% of a wax moistureproofing agent, and 1%-40% oi the aluminum salt of modified rosin and Petrex acid, said aluminum salt constituting a slip agent in a phase separate from the main body of the coating, said aluminum salt having a solubility of at least 1% toluene at a temperature of 25 0., and 0.5 grams thereof being at least partially insoluble in 25 cc. acetone at a temperature of 25 C., said modifiedros'in being characterized by properties of the general nature of those oi rosin, but with the difierence that it has a molecular weight within the range 5% to 400% greater than ordinary rosin in its pure state; that it has-a melting point, as determined by the capillary tube method, above 85 C. and

molecular weight higher than that of pure abieticacid, and said Petrex acid being a terpinene maleic anhydride complex comprising essentially 3-isopropyl-8-methyl-3:G-endo-ethylene delta 4-tetrahydro phthalic anhydride.

7. A thin, flexible, slippery, non-fibrous, transparent sheet provided with a moistureproofing coating containing a film-forming ingredient,

- and a wax moistureproofing agent. and as a slip agent, in a phase separate from the main body of the coating, an organic solvent-soluble double metallic carboxylate, said carboxylate having a solubility of at least 1% in toluene at a temperature of 25 C., and 0.5'grams of said slip, agent being at least partially insoluble in 25 cc. acetone ata temperature of 25 C., and being from the group consisting of the aluminum salt of rosin and modified rosin, the aluminum salt-of Petrex acid and modified rosin, aluminum salt of phthalic acid and benzoyl benzoic acid, and zinc aluminum rosinate, said modified rosin being characterized by properties of the general nature of those of rosin, but with the difference that it has a molecular weight within the range 5% to 400% greater than ordinary rosin in its pure state; that it has a melting point, as determined by the capillary tube method, above C. and higher than the melting point of pure abietic acid and of purified rosin when in the resinous state; that it is substantially tree from combined sulfurand hardening ubstances held in combination; that it has an iodine value lower than that of pure abietic acid; and that it has a molecular weight higher than that of pure abietic acid, and said Petrex acid being a terpinene maleic anhydride-complex comprising essentially 3-isopropyl-6-methyl-3 G-endo-ethylene-delta-4-tetrahydro phthalic anhydride, said slip agent being present in insufficient quantity to substantially impair the transparency of the sheet.

8. A thin, flexible, slippery, non-fibrous, transparent sheet provided with .a moistureproofing coating containing a film-forming ingredient, and a wax moistureproofing agent, and as a slip agent, in a phase separate from the main body 01 the coating, 1% to 40% of an organic solventsoluble double metallic carboxylate, said carboxylate having a solubility of at least 1% in toluene at a temperature of 25 C2, and 0.5 grams of said compound being at least partially insoluble in 25 cc. acetone at a temperature of 25 0., and being 'from the group consisting of the aluminum salt of rosin and modified rosin, the aluminum salt of Petrex acid and modified rosin, aluminum salt of phthalic acid and benzoyl benzoic acid, and zinc aluminum rosinate, said modified rosin being characterized by properties of the general nature of those of rosin, but with the difference that it has a molecular weight within the range 5% to 400% greater than ordinary rosin in its pure state: that ithas a melting point, as determined'by the capillary tube method, above 85 C. and higher than the melting point oi pure abietic acid and of purified rosin when in the resinous state: that it is substantially free from combined sulfur and hardening substances held in combination: that it has an iodine value lower than that of pure abietic acid: and that it has a molecular weight higher than that of pure abietic acid. and said Petrex acid being'a terpinene maleic anhydride complex comprising essentially 3 isopropyl-G- methyl 3:6 endo-ethylene-delta-4-tetrahydro phthalic anhydride, said compound being present in insufl'lcientquantity to substantially impair the transparency of the sheet.

5% of the coating, said carboxylate having a solubility of atleast 1% in toluene at a temperature of 0., and 0.5 grams of said carboxyiate being at least partially insoluble in 25 cc. acetone at a temperature oi 25 0., and being from the group consisting of the aluminum salt of rosin and modified rosin, the aluminum salt of Petrex acid and modified rosin, aluminum salt of phthalic acid and benzoyl benzoic acid, and zinc aluminum rosinate, said modified rosin being characterized by properties of the general nature of those 0! rosin, but with the difference that it has a molecular weight within the range 5% to 400% greater than ordinary rosin in its pure state that it has a melting point, as determined by the capillary tube method, above 85 0. and higher than the melting point of pure abietic acid and of purified rosin when in the resinous state; that it is substantially" free from combined sulfur and hardening substances held in combination: that it has an iodine value lower than that of pure abietic acid; and that it has a molecular weight higher than that oi pure abietic acid, and said Petrex acid being a terpinene maleic anhydride complex comprising essentially 3 isopropyl-6-methyl-3 G-endo-ethylene-delta- 4-tetrahydro phthalic anhydride.

10. A moistureproofing coating composition containing, dissolved in {an organic solvent, 9. film-forming ingredient, a wax moistureproofing agent and a double metallic carboxyiate, said carboxyiate having a solubility of at least 1% in toluene at a temperature of 25 0., and 0.5 grams of said carboxyiate being at least partially insoluble in 25 cc. acetone at a temperature of 25 0., and being from the group consisting of the aluminum salt of rosin and modified rosin, the aluminum salt of Petrex acid and modified rosin, aluminum salt of phthalic acid and benzoyl benzoic acid, and zinc aluminum rosinate, said modified rosin being characterized by properties of the general nature of those of rosin, butwith the difierenee that it has a molecular weight within the range 5% to 400% greater than ordinary rosin in its pure state;' that it has a melting point, as determined by the capillary tube method, above 85 0. and higher than the meltingpoint of pure abietic acid and of purified rosin when in the resinous state: that it is substantially free from combined sulfur and hardening substances held in combination: that it has an iodine value lower than that 01 pure abietic ac'id: and'that it has a molecular weight higher than that of pure abietic acid, and said Petrex acid being a terpinene maleic: anhydride complex comprising essentially 3-isopropyl-6.-methyl- 3:6 endo-ethylene delta-4-tetrahydro phthalic anhydride, said carboxyiate being esehnt in sufilcient quantity to separate as a distinct phase after the removal oi the solvent, but in insufi'icient quantity to substantially impair the transular weight within the range 5% to 400% greater than ordinary rosin in its pure state: that it has a melting point, as determined by the capillary tube method, above C. and higher than the melting point oi pure abietic acid and of purified rosin when in the resinous state: that it is substantially free irom combined sulfur and hardening substances held in combination; that it has an iodine value lower than that of pure abietic acid; and that it has a molecular weight higher than that 01 pure abietic acid, and said Petrex acid being a terpinene maleic anhydride complex comprising essentially 3-isopropyl- 6 methyl 3:6-endo-ethylene-delta-4-tetrahydro-phthalic anhydride.

l2. A moistureproofing coating composition containing, dissolved in an organicsolvent, a film-forming ingredient, a wax moistureproofing agent and 1% to 40% (based on the solids content) oia double metallic carbonlate, said in toluene at a temperature of 25 0., and 0.5

carboxyiate having a solubility of at least 1%.

grams oi said carboxyiate being at least para melting point, as determined by the capillary tube method, above 85C. and higher than the melting point of pureabietic acid and oi purified rosin when in the resinous state: that it is substantially tree from combined sulfur and hardening substances held in combination; that it has an iodine value lower than that of pure abietic acid; and that it has a molecular weight higher than that of pure abietic acid, and said Petrex acid being a terpinene maleic anhydride complex comprising essentially B-isopropyl-B-methyl- 3:6 endo-ethylene-delta-4-tetrahydro phthalic anhydride, said carboxyiate being present in sufiicient quantity to separate as a distinct phase after the removal 01' the solvent, but in insufiicient quantity to substantially impair the transparency of the coating.

13. A moistureproofing coating composition containing, dissolved in an organic solvent, a film-forming ingredient, a wax moistureproofing agent and a double metallic carboxyiate, said carboxyiate having a solubility of at least 1% in toluene at a temperature of 25 0., and 0.5 grams of said carboiwlate being at least partially insoluble in 25 cc. acetone at a temperature of 25 0., and being from the group consisting of the aluminum salt of rosin and modified rosin, the aluminum salt oi Petrex acid and modified rosin, aluminum salt of phthalic acid and benzoyl benzoic acid, and zinc aluminum rosinate, said modified rosin-being characterized by properties of the general nature 01' those of rosin. but with the difference that it has a molecular weight within the range 5% to 400%. greater than ordinary rosin in its pure state: that it has a melting point, as determined by the capillary tube method, above 85' 0. and higher than the melt-- ing point oi pure abietic acid and of purified rosin when in the resinous state: that it is substantially tree from combined sulfur and hardening substances held in combination: that it has an iodine value lower than that of pure abietic acid; and that it has a molecular weight higher than that of pure abietic acid, and said Petrex acid being a terpinene maleic anhydride 2,284,565 complex comprising essentially 3-lsopropyi-6- 14. The method of producing a thin, flexible,

slippery, high-stick temperature, transparent,

moistureproof sheet which comprises applying to a transparent, non-fibrous base sheet a moistureprooflng coating composition containing in solution 30%-70% of a film-forming ingredient, 0.5%-l0% of a moistureproofing agent, and 1%-40% of a slip agent of the group consisting of the aluminum salt or rosin and modified rosin. the aluminum salt of Petrex acid and modified rosin, aluminum salt of phthalic acid and benzoyl benzoic acid, and zinc aluminum rosinate, and drying said coating composition whereby to cause said slip agent to separate as a distinct phase from the main body of the coating, said modified iodine value lower than that of pure abietic acid;

and that it has a molecular weight higher than that of pure abietic acid, and said Petrex acid being a terpinene maleic anhydride complex' comprising essentially 3 isopropyl-S-methyl- 3:6 endo-ethylene-delta-4-tetrahydro phthalic' anhydride.

15. The method of producing a thin, flexible, slippery, high-stick temperature, transparent, moistureproof sheet which comprises applying to a transparent, non-fibrous base sheet a moistureproofing coating composition containing in solution a film-forming ingredient, a moistureproofing agent, and a double metallic carbozzylate, said carboxylate being present in sufllcient quantity to separate as a distinct phase after the removal of the solvent, but in insufilcient quantity to substantially impair;the transparency of the coating, and being from the group consisting of the aluminum salt of rosin and modified rosin, the aluminum salt of Petrex acid and modified rosin, aluminum salt of phthalic acid and benzoyl benzoic acid, and zinc aluminum rosinate, said modifled rosin being characterized by properties oi the general nature of those of rosin, but with the difference that it has a molecular weight within the ,range 5% to 400% greater than ordinary rosin in its pure state: that it has a melting point, as determined by the capillary tube method, above 85' C. and higher than the melting point of pure abietic acid and or purified rosin when in the resinous state; that it is substantially free from combined sulfur and hardening substances held in combination; that it has an iodine value said carboxylate to separate as a, distinct phase from the main body of the coating.

16. The method of producing a thin, flexible, slippery, high-stick temperature, transparent, moistureproof sheet which. comprises applying to a transparent, non-fibrous base sheet a moisture proofing coating composition containing in solution 30%-70% of a film-forming ingredient, 0.5%-10% of a moistureproofing agent, and

l%-40% of the aluminum salt of modified rosin.

and Petrex acid, and drying said coating composition whereby to cause said aluminum salt to separate as a distinct phase from the main body of the coating, said modified rosin being characterized by properties of the general nature of those of rosin,' but with the difierence that it has a molecular weight within the range 5% to 400% greater than ordinary rosin in its pure state: that it has a melting point, as determined by the capillary tube method, above C. and higher than the melting point of pure abietic acid and of purified rosin when in the resinous state; that it is substantially free from combined sulfur and hardening substances held in combination; that it has an iodine value lower than that of pure abietic acid; and that it has a molecular weight higher than that of pure abietic acid, and said Petrex acid being a terpinene maleic anhydride complex comprising essentially 3-isopropyl- 6-methyl-3:6-endo-ethylene-delta- 4 tetrahydro 'phthalic anhydride.

17. The method of producing a thin. flexible,

slippery, high-stick temperature, transparent,'

moistureproof sheet which comprises applying to a transparent, non-fibrous base sheet a moistureproofing coating composition containing in solution a film-forming ingredient, a moistureproofing agent and 1% to 40% (based on the solids content) or a double metallic carboxylate, said carboxylate being present in suflicierit quantity to separate as a distinct phase after the removal of the solvent but in insufilcient quantity to substantially impair the transparency of the coating, and being from the group consisting of the aluminum salt of rosin and modified rosin, the aluminum salt of Petrex acid and modified rosin, aluminum salt of phthalic acid and benzoyl benzoic acid, and zinc aluminum rosinate, said modified rosin being characterized by properties of the general nature of those of'rosin, but with the difference that it has a molecular weight within the range 5% to 400% greater than ordinary rosin in its pure state; that it has a melting point, as determined by the capillary tube method, above 85 C, and higher than themelting point of pure abietic acid and of purified rosin when in the resinous state; that it is substantially free from combined sulfur and hardening substances held in combination; that it has an iodine value lower than that of pure abietic acid,

and said Petrex acid being a terpinene maleic anhydride complex comprising essentially 3-isopropyl-6-methyl-3 6-endo-ethylene-delta- 4 -tetrahydro phthalic anhydride, and drying said coating composition whereby to'cause said carboxylate to separate as a distinct phase from the main body of the coating in an amount not exceeding 5%.

18. The article of claim 9 in which the double metallic carboxylate is the aluminum salt of modified rosin and of Petrex acid, said modified rosin being characterized by properties of the general nature of those of rosin. but with the diftference that it has a molecular weight within the range 5% to 400% greater than ordinary rosin in its pure state; that it has a melting point, as determined by the capillary tube method, above 85 C. and higher than the melting point of pure abietic acid and of purified rosin when in the resinous state; that it is substantially free from combined sulfur and hardening substances held in combination; that it has an iodine value lower than that of pure abietic acid; andthat it has amolecular weight higher than that of pure abietic acid, and said Petrex acid being a t'erpinene maleic anhydride complex comprising essentially 3-isopropy1-6-methyl-3:6-endo-ethylene-delta-4 5 tetrahydo phthalic anhydride.

DANIEL D. LANNING. 

